#include "stdio.h"
mFILE *mfopen(const char *filename, const char *mode)
{
	int fd = -1;
	if(strcmp(mode, "r") == 0)
	{
		fd = open(filename, O_RDONLY);
	}
	else if(strcmp(mode, "w")== 0)
	{
		fd = open(filename, O_CREAT|O_WRONLY|O_TRUNC, 0666);
	}
	else if(strcmp(mode, "a") == 0)
	{
		fd = open(filename, O_CREAT|O_WRONLY|O_APPEND, 0666);
	}
	if(fd < 0) 
		return NULL;
		
	mFILE *mf = (mFILE*)malloc(sizeof(mFILE));
	if(!mf) 
	{
		close(fd);
		return NULL;
	}
	
	mf->fileno = fd;
	mf->flag = FLUSH_LINE;
	mf->size = 0;
	mf->cap = SIZE;
	return mf;
}
void mfflush(mFILE *stream)
{
	if(stream->size > 0)
	{
		// 写到内核⽂件的⽂件缓冲区中! 
		write(stream->fileno, stream->outbuffer, stream->size);
		// 刷新到外设 
		fsync(stream->fileno);
		stream->size = 0;
	}
}
int mfwrite(const void *ptr, int num, mFILE *stream)
{
	// 1. 拷⻉ 
	memcpy(stream->outbuffer+stream->size, ptr, num);
	stream->size += num;
	// 2. 检测是否要刷新 
	if(stream->flag == FLUSH_LINE && stream->size > 0 && stream->outbuffer[stream->size-1]== '\n')
		mfflush(stream);
	return num;
}
void mfclose(mFILE *stream)
{
	if(stream->size > 0)
		mfflush(stream);
	close(stream->fileno);
}
